A new Luci menu entry appeared in recent SNAPSHOT builds: System ¦ Plugins.
I have tracked the appearance down to Commit 617f364. But it isn’t easy to deduce what it is for.
Anyone able to provide more detail?
The dev would have the full details. 
This is what shows in the notes though:
”provide UI to configure behaviour of plugins”
Saw that, but still puzzled.
@systemcrash Are you able to enlighten us?
What difference might there be between Plugins & Packages?
Why does the Plugins menu appear before any Plugins are installed?
How might one install a Plugin?
It was just added to snapshot. I think you should be waiting and be patient what happens with it further. It does not seams finished yet... Again it just appeared in snapshot.
Plugins are intended to augment the UI and dispatcher operations. This currently makes possible things like 2FA for login and additional HTTP headers. Other areas of operation may be realised.
Some contributors want to add features which mean that they become always on for everyone. Plugins allow controlling this aspect.